The ability to learn and produce sequential movements is fundamental to adaptive behavior. Such learning is often implicit, occurring without awareness of the optimal sequence of movements. The basal ganglia and cerebellum have been hypothesized to be critical for the acquisition of implicitly learned sequential movements. However, results obtained in neuroimaging and neuropsychological studies provide an inconsistent picture of the contributions of these subcortical structures. Two recent findings may provide insight into such discrepancies. First, motor learning and performance may depend on the movement cues, a variable that has received little attention in sequence learning studies. Second, motor impairments may lead to secondary cognitive deficits due to increased attention devoted to controlling the impaired movement. The proposed studies seek to address these novel ideas in the context of subcortical control of implicit motor learning. Methods include behavioral testing and functional imaging with neurologically healthy and impaired individuals. The findings are relevant to the development of rehabilitation strategies for persons with motor disorders as the proposal seeks to identify conditions under which patients with either cerebellar or basal ganglia disorders are able to learn new skills as well as conditions in which they are impaired.